Field of the Invention
The present invention relates to a printing apparatus to which a stacker can be connected and a control method.
Description of the Related Art
A machine called a stacker that can stack large quantities of printed items from a finisher with favorable stackability is used in production printing that covers the printing of commercial printing deliverables. There is a stacking tray in the stacker that descends as printing deliverables are stacked, and even at the very least, several thousands of sheets of printing deliverables can be stacked thereon. Also, when a stacked deliverable is to be conveyed, there are many cases of configurations in which a deliverable can be transported using an entire stacking tray, a dedicated cart, or the like, so that there is no need for a user to manually move deliverables to the cart. Also, there is a stacker equipped with multiple stacking trays so that the space inside it is used efficiently and even more deliverables can be stacked (Japanese Patent Laid-Open No. 2010-143734). For example, by providing two stacking trays in a stacker that has a capacity in which 5000 sheets of an A3 sized deliverable can be stacked, 10,000 sheets can be stacked, which is double, if the deliverable is A4 size.
There is also a stacker that has a function in which deliverables are automatically discharged to the outside of the stacker when the amount of deliverables in the stacker has reached the permissible amount for stacking. This stacker is configured such that after deliverables have been temporarily discharged to the outside of the stacker, the stacking of deliverables inside the empty stacker can be continued automatically. Also, after the deliverables stacked inside the stacker have been temporarily discharged to the outside of the stacker, the stacking of deliverables inside the stacker is started again, and once the permissible amount has been reached again, the stacker becomes fully stacked for the first time. In other words, at this point a need arises for the first time for the user to remove the stacked deliverables in order for the printing and stacking of a deliverable to continue. In this way, the stacker that has the function in which deliverables are automatically discharged to the outside of the stacker can continuously print for extended periods of time without intervention from a user.
However, there is an interrupt print function in which one print job interrupts the middle of another print job that is being performed. This is executed when there is a change to job scheduling due to a print job request from a client, for example. With the interrupt print function, the current printing is interrupted, and a print job with a high degree of priority can be executed with priority. Also, the interruption processing at this time is not just processing in which printing is quickly stopped, but rather control is performed so as to stop the print job at a favorable break point, such as a break at the end of a deliverable set or the end of a bundle in post-processing. Accordingly, a print job can be inserted by interrupting another print job, while also performing control so as to suppress wasted deliverables as much as possible.
The aforementioned stacker, that has a function in which deliverables are automatically discharged to the outside of the stacker, is configured such that the deliverables that are stacked inside the stacker cannot be removed as long as a bundle of the deliverables discharged outside of the stacker has not been removed. Assume that a bundle of deliverables has been previously discharged to the outside of the stacker for this reason, and that sheets of another job are discharged into the stacker using the above-described interrupt print function. In this case, the bundle obtained by performing interrupt printing cannot be removed as long as the bundle of deliverables that was previously discharged to the outside of the stacker has not been removed.